Starting point: new sample and new tip are loaded in the STM. Tip-sample distance is “large” (i.e. few millimeters). STM is in lowest position, inside the centering pin and 1K-shield-window is open. 1K pot flow is set for normal cooling operations (~6-7mbar). All 3He is inside the system and V1 is closed.
It is possible to approach immediately after the STM has reached the top position (measurement position in the middle of the magnet), but there will be initially a lot of thermal drift as the sample/tip are initially at room temperature. They will thermalize rather soon, within 1 hour, at about 40~50K (there will be less drift then).
At this point (when tip and sample are loaded) the cooling procedure can start. The STM will be cooled first to about 2K by desorbing and condensing the 3He that is now inside the sorb pump.